In a prospective evaluation of the relationship between Helicobacter pylori infection and gastro-oesophageal reflux disease (GORD), 93 consecutive patients (47 female: 46 male: mean age, 46 years: range 13-93) with symptoms and endoscopic evidence of GORD were studied. A total of 50 patients (54%) were H. pylori-positive on gastric antral biopsies. No significant correlation was detected between H. pylori status and grade of oesophagitis. The prevalence of H. pylori infection showed a gradual increase with age. Of 64 patients with a hiatal hernia, 28 (44%) had histological evidence of H. pylori infection of the hernia mucosa; 27 of these patients (96%) had associated H. pylori in the gastric antrum. Of the 36 patients whose hiatal hernia was H. pylori-negative, only 6 (17%) had antral H. pylori (P < 0.001). Of the 8 patients found to have Barrett's oesophagus, only 1 had H. pylori detected on the Barrett's mucosa. Our results do not support the presence of a significant association between H. pylori infection and GORD.